Steam-turbine.



PATENT-ED MAY 23, 1905.

J. STUMPF. STEAM TURBINEJ APPLICATION FILED SEPTKB. 190a.

Witnesses.

Inventor".

Johann Stumpf.

ofships.

UNITED STATES Patented May 23, 1905.

PATENT OFFICE.

J OHANN STUMPF, OF OHARLOTTENBURG, GERMANY, ASSIGNOR TO GEN- ERALELECTRIC COMPANY, A CORPORATION OF NEW YORK.

STEAM-TURBINE.

SPECIFICATION forming part of Letters Patent No. 790,406, dated May 23,1905.

' Application filed September s, 1903. Serial No. 172,236.

To a whom it may concern:

Be it known that I, J OHANN STUMPE, asubject of the King of Prussia,German Emperor, and a resident of 27 Rankestrasse, Oharlottenburg, nearBerlin, Kingdom of Prussia, German Empire, have invented certain new anduseful Improvements in Steam or Gas Turbines for the Screw-Propellers ofShips, of which the following is an exact specification.

My invention relates to improvements in steam or gas turbines for-thescrew-propellers In driving screw propellers by means of steam or gasturbines it is a great disadvantage that the number of revolutions ofthe turbines is so great that the velocity of the screw-propellerseffects the formation of a vacuum in the water, thereby reducing theeffect of the turbines. In order to avoid too great a velocity of thescrew-propellers, turbines with two turbine-wheels rotating in oppositedirections have been usedthat is to say, turbines which have at leasttwo turbine-wheels turnable around the same axis,

the steam flowing from one turbine-wheel to the second one. In theseturbines the velocity of the turbine-wheels is considerably reduced andit can be attained that by the arrangement of the two turbine-wheels thevelocity amounts only to one-half of the velocity of a turbine providedwith only one turbine-wheel.

For each turbine-wheel a special screw-propeller or system ofscrew-propellers is provided. These screw propellers also rotate aroundthe same axis. I attain this by arranging the turbines as well as thescrewpropellers upon two separate shafts, one of which shafts is hollowand the other one of which is situated in this tubular shaft.Advantageously the screw propeller situated near the ship-hull is fixedto the tubular shaft, while the othenscrew-propeller is fixed to thesolid shaft.

If two screw-propellers are situated one behind the other one, the firstscrew-propeller gives a certain velocity to the water and the secondpropeller must give a greater velocity to the water moved by the firstscrew-propeller. In order to effect this, either the velocity of thesecond screw-propeller must be propeller must be greater than the angleof inclination of the wings of the first screwpropeller. It will beunderstood that all these means, or two of the same, may be usedsimultaneously.

Now it has proved advantageous to have equal velocities for bothscrew-propellers in order to avoid the formation of a vacuum by thevelocity of the second screw-propeller surpassing the limits allowed, asmentioned above. Therefore screw-propellers of different shape are used,according to the present invention. In practice it has been shown thatby enlarging the wings of the second screwpropeller or the angle ofinclination of the same the effect of both screw-propellers is not madeequal, but the second screw-propeller has only about one-third of thetotal effect ,of the propellers, whereas the first screw-propeller hastwo-thirds of this eflect.

In turbines with two turbine-wheels rotating in opposite direction theprimary wheel that is to say, the wheel impinged upon by fresh steamhasabout two-thirds of the total energy of the turbine, whereas the secondwheel impinged upon by the exhaust-steam of the primary wheel has onlyone-third of the energy of the turbine. Therefore, according to thepresent invention, the second screw-propeller is coupled with thesecondary turbine-wheel and the first screw-propeller with the primaryturbine-wheel.

The screw-propellers naturally move in opposite directions, which has agreat advantage. The first propeller gives a certain longitudinalmovement to the water, but at the same time gives a rotating movement tothis water-that is to say, the water moves on a screw-line. In a certaindistance after the first screw-propeller the second screw-propellerrotates in an opposite direction and the wings of the secondscrew-propeller rotate the water in the opposite direction, herebyaugmenting the useful effect of the second screw-propeller.

In order to make my invention more clear, I refer to the accompanyingdrawings, in which Figure 1 is a scheme showing the arrangement of theturbine-wheels and screw-propellers. Fig. 2 shows part of thecircumference of the turbine-wheel rims. Fig. 3 shows the inventionapplied to a turbine with four bucket or vane rims.

In the drawings, ais a solid shaft. bular shaft surrounding the same.

0 is a primary turbine-wheel fixed to the tubular shaft 6, and (Z is asecondary turbinewheel fixed to the solid shaft a.

e is the first screw-propeller fixed to the hollow shaft and primarywheel, and f is the second screw-propeller fixed to the solid shaft andsecondary wheel. The wings of the propeller f are larger than the wingsof the propeller a. It will be understood, however, that just as wellthe angle of inclination of the wings of the propeller f may be madelarger than the angle of inclination of the wings of the propeller e.

g represents the nozzles through which the steam flows upon the primarywheel. As will be seen from Fig. 2, the steam acts at first upon theturbine-wheel e and after leaving the vanes of this turbine-wheel actsupon the turbine-Wheel (Z.

It will be understood that any kind of turbine-wheels may be usedso, forinstance, turbines may be used in which guide-vanes are arranged betweenthe turbine wheels, which guide the steam from one turbine-wheel to thesecond one, or turbines with several turbine-wheels may be usedas, forinstance,

I) is a tuturbines with four wheels, as shown in Fig. 3. In thisconstruction four turbine-wheels 0 (Z' c d are provided. The fresh steamacts upon the turbine-wheels 0' (Z c 0 It will be clear that thedrawings illustrate one example and that the arrangement may be modifiedin different waysas, for instance, instead of one screw-propellerseveral screwpropellers may be arranged upon each shaft and severalshafts situated one within the other may be provided, upon each of whichshafts a special turbine-wheel is situated.

Having thus fully described the nature of this invention, whatIdesire tosecure by Letters Patent of the United States is- In an elastic-fluidturbine, the combination of primary and secondary bucket wheels mountedto revolve in opposite directions, the primary wheel having a greatertorque than the secondary wheel, a nozzle for converting the pressure ofthe fluid into velocity and discharging it against the primary wheelfrom which it enters the secondary wheel, and load devices connected tothe wheels by shafts, the load device adjacent to the turbine beingconnected to the primary wheel, or one having the greater torque, andthe one more remote connected to the secondary wheel, or one having thelesser torque, substanially as and for the purpose set forth.

In testimony whereof I have signed my name to this specification in thepresence of two subscribing witnesses.

JOl-[ANN STUMPF.

Witnesses:

HENRY HAsrER, WOLDEMAR HAUP'I.

